Sn-doped g-C₃N₄ as a novel photoelectrocatalyst for water oxidation

The photocatalytic performance of graphitic carbon nitride can be enhanced multifold by introducing suitable dopants. Here we report incorporating a cost-effective, non-toxic and abundant element, i.e., tin, in elongated semiconducting carbon nitride (g-C₃N₄). A novel procedure was used to introduce varying amounts of tin to the g-C₃N₄ framework. The new photocatalysts (Sn–CN) were characterized by X-Ray Diffraction (XRD) and FT-IR measurements, confirming the absence of tin oxide and incorporation of tin in the g-C₃N₄ backbone. The SEM, EDX, TEM and XPS measurements demonstrated the elongated morphology and the presence of tin in the composite materials. BET measurements showed a relative increase in the specific surface area for the composites. The optical measurements showed enhanced solar light absorption and promoted the charge carrier's separation after the insertion of Sn to g-C₃N₄. Photoelectrochemical water dissociation measurements showed that 10% tin doping increased the activity of g-C₃N₄ to water photo-oxidation about four times. This improvement was analyzed by electrochemical impedance spectroscopy measurements.